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DEVELOPMENT AND APPLICATION OF PROMISING TECHNOLOGIES FOR FIRING COAL-WATER FUELS

DEVELOPMENT AND APPLICATION OF PROMISING TECHNOLOGIES FOR FIRING COAL-WATER FUELS Coal-Gen Europe 2008 F. Serant , K. Agapov , A. Kuzmin, Yu. Ovchinnikov, L. Pugach SibCOTES, NSTU cotes@cotes.sib.ru Novosibirsk Russian Federation. CONTENTS.

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DEVELOPMENT AND APPLICATION OF PROMISING TECHNOLOGIES FOR FIRING COAL-WATER FUELS

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  1. DEVELOPMENT AND APPLICATION OF PROMISING TECHNOLOGIES FOR FIRING COAL-WATER FUELS Coal-Gen Europe 2008 F. Serant, K. Agapov, A. Kuzmin, Yu. Ovchinnikov, L. Pugach SibCOTES, NSTU cotes@cotes.sib.ru Novosibirsk Russian Federation

  2. CONTENTS Problems and prospects for coal-water firing at power generation installations Experience of application of coal-water fuel at Novosibirsk CHP-5 Plant & Belovskaya PP Advanced coal-water technologies developed together with Novosibirsk State Technical Institute & Novosibirskteploelectroproect Main conclusions - 2 -

  3. Power industry & coal-water fuel in Russia Tons of coal equivalent - 3 -

  4. Advantages of coal-water fuel Coal-water slurry is a relatively new type of fuel for small- and large-scale power installations. It has a number of advantages compared to conventional fuels: • Long-distancepipeline transition • No explosion hazard • Lower NOx and SOx emission level - 4 -

  5. Requirements for coal-water fuel General requirements for coal-water fuels: • Suitable viscosity - about 0.5–1.0 Pa·s with shear rate 100 s-1 • Certain stability of properties when stored in tanks for 12-18 months • Ensuring the conditions for stable direct combustion: acceptable heating value, reactivity, and good dispersing properties (drops up to 350 μm) • Fired fuel should ensure efficient combustion, as well as reduced emissions • Eliminate covering and slagging of heating surfaces General requirements for coal-water fuelsproduction process: • Acceptable power inputs per 1 ton of product • Moderate wearand metal intensity per 1 ton of the product • Long overhaul life for the elements (mills, cavitators, dispersers, fuel nozzles) • Automation ensuring proper operation level - 5 -

  6. Coal-water fuel combustion on a 200 MW unit at Belovskaya Power Plant Coal-water slurry conditions: Kuznetsky coal, grades D (long-flame coal) Kuznetsky G (gas coal) Qir =15.1 MJ/kg Wr = 39% Ar =9% Nr = 1.45% Density ρ=1180÷1220 kg/m3 Viscosity μ = 0.5÷1.2 Pa·s • Boiler PK-40-1: • Steaming capacity = 320 t/h • Furnace heat release rate qv= 130 kW/m3 • Furnace cross-section heat release rate qF= 3.8 MW/m2 • 6000 tons of coal-water fuel were fired - 6 -

  7. Application of coal-water fuel at Novosibirsk CHP-5 Plant • 262 km-long coal slurry pipeline • 4 million tons of coal-water fuel per year • 3 million tons of dry coal per year - 7 -

  8. Coal-water fuel handling and storage system Two tanks (20 000 m3 each) with hydro mixers Air compressor Compressed air - 8 -

  9. Coal-water fuel combustion on boiler at Novosibirsk CHP Plant • Boiler performance: • Steaming capacity - 670 t/h • 1 boiler was completely re-equipped for coal-water fuel firing (together with Snamprogetti) • 3 boilers fired it together with conventional Kuznetsky coal (grades D (long-flame coal) and G (gas coal)). • Low heat release rates - qv = 95 kW/m3 and qF = 3.4 MW/m2. • Coal-water fuel conditions: • Coal concentration in the coal-water fuel - 54.6 - 55.8% • Coal-water fuel density – ρ=1.21 g/cm3 • Ash content Ad=9.5 % • Calorific value Qir =13.6-14.4 MJ/kg Coal quality: Qir =22,7 MJ/kg Ad=12.5 % Wr =14.6% - 9 -

  10. Conclusions after coal-water fuel firing at Belovskaya PP and Novosibirsk CHP-5 Plant Switching of the existing PC-fired boilers to coal-water fuel without any additional reconstruction results in the following: • Lower gas temperature in the flame kernel (by 100-150°С) • Lower cost-efficiency of combustion (by 2.5-3.3%) • Higher gas temperature at the furnace tail (by 35-45°С) and downstream the boiler by 15-20°С • Lower NOx level under certain conditions (by 25-35%) To eliminate adverse effects the boilers need some re-engineering, incl.: • Heat insulation of the furnace to increase gas temperature within the flame kernel • Changed superheater and economizer surfaces • Finer coal grinding • Higher hot air temperature Transmission system for coal-water fuel (Belovo – Novosibirsk) with conventional milling and mixing with water has some disadvantages: • Limited time of being in a stable condition • Abrasivity of coal-water fuel, which causes considerable wear of pumps, gate valves, fuel nozzles, etc. • Need to use surface-active substances - 10 -

  11. Cavitation of coal-water fuel Technology developed together with company NovosibirskTeploelectroproekt Capacity from 5 to 300 t/h of sourse coal Coal-water fuel stability – more than 24 months - 11 -

  12. Coal-water technologies developed by Novosibirsk State Technical University (NSTU) 1 – coal hopper 2 – crusher 3 – feeder 4 – desintegrator 5 – separator 6 – cyclone 7 – FDF 8 – PC bunker 9 – feeder 10 – cavitators 11 – raw oil tank (oil and fuel oil residue) 12 – daily tank for composite liquid fuel 13 – recirculation line of composite liquid fuel 14 – water-supply tank 15 – peat hopper 16 – screen 17 – flotation plant 18 – peat gel feed line 19 – feeding pump of composite liquid fuel 20 – feed line of composite liquid fuel 21 – FDF 22 – feed line for coal-water mixture after the first cavitation stage - 12 -

  13. Coal-water production technology features • Stability of the system is more than 1 year • Basic methods of stabilization: • Mechanical-chemical activation of solid phase during grinding in a desintegrator • Mechanical-chemical activation of liquid phase in a cavitator • Creation of stable physical-chemical fuel system through profound homogenization of activated phase in a cavitator - 13 -

  14. Main equipment for the technology Desintegrator is a high-speed mill with percussive-smashing effect. Desintegrator output is 3 t/h Activation of coal particles is realized through deformation of coal structure and through creation of micro-defects on the surface of coal particles. - 14 -

  15. Main equipment for the technology Cavitator functions: • Further grinding of solid phase material • Homogenization of liquid and solid particles mixture • Creation of stable physical chemical liquid fuel system • Major feature - Shock-thermal effect in the cavitator zone; • This impact leads to: • activation of liquid • destruction of connections in the clusters of the liquid • creation of free radicals and active molecules. Cavitator: output - 3 tons per hour ACLF - 15 -

  16. Production of synthetic composite liquid fuel Main technical characteristics of the new technology: • Specific energy consumption ~ 14-17 kW per ton of product • Specific metal consumption ~0.45-0.50 t per ton of product in terms of the main equipment • Reasonable cost of equipment • Production area ~ 8 m2/t - 16 -

  17. Module for synthetic composite fuel production - 17 -

  18. Received fuels & their combustion • Received fuel: • Line 1: Wr = 64 %, coal – 20 %, peat – 8 %, oil – 8 %, Ad =28 %; • Line 2: Wr = 54.5 %, coal – 45.5 %, Ad =27.8 %; • Line 3: Wr = 56.05 %, coal – 17 %, peat – 10 %, fuel oil – 17 %, Ad =19.5 %; • In addition, coal-based fuel without any peat component was received: • Line А: Wr= 35.5%, coal – 39.5%, oil - 25%, Аd= 10.3 %; • Line G: Wr= 48.6%, coal – 43.4%, oil - 8%, Ad= 19.5 %. • Mail results of fuel lines studies: • Viscosity of the synthetic composite liquid fuel does not depend on the temperature within the operating temperature range and on the shear rate within the operating velocities, it depends on the composition and is similar to operating viscosity of fuel oils. Synthetic composite liquid fuel is a thixotropic fluid. • Combustion process confirmed reliable flame ignition of sprayed synthetic composite liquid fuel and its independent stable combustion. • Emissions when firing coal-water fuel are: NOx = 50-100 mg/Nm3 (with O2 = 6 %), SO2 =140-200 mg/Nm3. - 18 -

  19. Conclusions • Presented technologies make it possible to produce a fundamentally new type of synthetic fuel based on coal, water and other components; • Rheological, sedimentation, heat-and-power requirements for this fuel were defined; • In order to burn synthetic composite fuel on existing PC-fired boilers with good efficiency, it is necessary to reconstruct such boilers; • The fuel meets the requirements set for the coal-water fuels; • New composite fuel can be used both for firing in various combustion chambers, and as a fuel for internal-combustion engines, gas turbine fuel and fuel for gasifiers, or instead of oil fuel for boilers and TPPs; • Research works for the preparation and combustion of synthetic composite liquid fuel making use of local fuels (different grades of peat), coal treatment products, wood waste, farm and oil refinery waste are still in progress. - 19 -

  20. Thank you for your attention!

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